Neutrino Physics - Lecture 6 Steve Elliott LANL Staff Member UNM Adjunct Professor ,

Spring 2007Steve Elliott, UNM Seminar Series2 Lecture 6 Outline Reactor Neutrinos (Many slides from Bob Mckeown) The neutrinos Past experiments What we know and what we want to learn

Spring 2007Steve Elliott, UNM Seminar Series3 Reactor Experiments CHOOZ, Palo Verde Double CHOOZ, Daya Bay Texono –Neutrino magnetic moment –Coherent scattering

Spring 2007Steve Elliott, UNM Seminar Series4 Distance (m) P( e  e ) Dominant  12 Oscillation Subdominant  13 Oscillation Anti- e Disappearance

Spring 2007Steve Elliott, UNM Seminar Series5  13 90, 95, 99% CL hep-ph/  m 23 2 from SK atmospheric Chooz Solar

Spring 2007Steve Elliott, UNM Seminar Series6 Neutrino Oscillation Studies with Nuclear Reactors e from n-rich fission products detection via inverse beta decay ( e +p  e + +n) Measure flux and energy spectrum Improve detectors, reduce background Variety of distances L= 10m-250km

Spring 2007Steve Elliott, UNM Seminar Series7 Detection Signal Coincidence signal: detect Prompt: e + annihilation  E  E prompt +E n +0.8 MeV Delayed: n capture 180  s capture time p + e 511keV   2.2 MeV  d n

Spring 2007Steve Elliott, UNM Seminar Series8

Spring 2007Steve Elliott, UNM Seminar Series9 KamLAND uses the entire Japanese nuclear power industry as a long­baseline source Kashiwazaki Takahama Ohi

Spring 2007Steve Elliott, UNM Seminar Series10

Spring 2007Steve Elliott, UNM Seminar Series11 Solar :  m 2 = 5.5x10 -5 eV 2 sin 2 2  = G.Fogli et al., PR D66, , (2002) Ratio of Measured and Expected e Flux from Reactor Neutrino Experiments

Spring 2007Steve Elliott, UNM Seminar Series12 Measurement of Energy Spectrum

Spring 2007Steve Elliott, UNM Seminar Series13 KamLAND best fit :  m 2 = 7.9 x eV 2 tan 2  = 0.45 KamLAND fixes mass Solar fixes angle

Spring 2007Steve Elliott, UNM Seminar Series14 Geoneutrinos Nature 436, 499 Two estimates of total power dissipated by Earth 44.2 ± 1 TW 30 ± 1 TW 19 TW is estimated to be due to radiogenic sources, 84% due to Th/U decay, some mantle studies imply it might be larger.

Spring 2007Steve Elliott, UNM Seminar Series15 New Reactor Proposals Braidwood, Il Daya Bay, China Chooz, France ~1.5 km baseline Deeper/bigger Near/Far KASKA

Spring 2007Steve Elliott, UNM Seminar Series16 Detector Design Studies horizontal cylinder spherical

Spring 2007Steve Elliott, UNM Seminar Series17 Daya Bay Each detector: Inner zone 20 tons Gd-doped LS Defined by acylic Outer zone just LS Outermost zone just mineral oil 224 pmts Sin 2  13 ~ Constr Data start 2009

Spring 2007Steve Elliott, UNM Seminar Series18 Double Chooz Sin 2  13 ~ Data 2008 Daya Bay and Double Chooz have similar concepts for LS

Spring 2007Steve Elliott, UNM Seminar Series19 New Properties Unexpected new neutrino properties –CPT invariance violation –Equivalence principle violation –Lorentz violation Would appear as oscillation effects but with a departure from the classic oscillation wavelength energy dependence Mass varying neutrinos –Dark energy scale {2 meV} is similar to scale of neutrino mass splitting {(9 meV) 2 } –Might be observable in oscillation,  experiments

Spring 2007Steve Elliott, UNM Seminar Series20 Magnetic Moments Do neutrinos have magnetic moments? Dirac neutrinos can posses static moments Majorana neutrinos can possess transition moments SM predicts very small value: 3x (m /eV)  B Present limits: <9x  B Measurements hard because the possible EM and known WI contributions are similar in magnitude. Astrophysical constraints in addition to reactor/accelerator limits. Beta beams and tritium sources have also been proposed.

Spring 2007Steve Elliott, UNM Seminar Series21 Electron elastic scattering experiments Neutrino elastic scattering cross sections scale as E 2, whereas the  B interaction are mostly energy independent. Thus the EM cross section may dominate at low energies. Reactor neutrino experiments are the best to date. Most recent: TEXONO expt. in Taiwan PR D75 (2007)

Spring 2007Steve Elliott, UNM Seminar Series22 Coherent nuclear scattering experiments 1 MeV neutrino with  B scattered on a N=Z spin 0 nucleus has Spin contributions enhance SM cross section. For N≠Z, isospin dependent terms contribute. High A nuclei have low recoil energies. Like ES, largest ratio is for low recoil energy J.Phys.Conf.Ser. 39 (2006) 266